Van den Reijen et al. (2013) joggled with P-values

Because of complex problems adolescents often fail to complete their course of treatment. Van der Reijen and colleagues aimed to investigate whether gender and symptom severity predict course of treatment. The English summary is truly puzzling. First of all, the aim of the study does not relate to the background info. Complexity (seen as having both psychiatric and behavioural problems) as background concept is different from symptom severity (many psychiatric problems). Secondly, the method section does not indicate the design or type of analyses. The authors attempted to find out if treatment outcome could be predicted by symptom severity and gender differences “of 127 male adolescent patients” (something went wrong in translation). But summary results include only inter-rater reliability, not symptom and gender differences. Finally, the conclusion is descriptive more than persuasive: “the questionnaire was not able to predict accurately whether patients would complete their treatment”. However, the devil is in the full text…

Schoevaerts et al. (2013) tested to explore?

Schoevaerts and collegeas (2013) estimate the incidence and evolution of compulsory admissions in Belgium and the Netherlands by pooling and analysing available register data. The epidemiological exploration shows an increase in the number of involuntary psychiatric admissions. That increase is without dispute. However, some question are raised by the presentation of the statistics and the interpretation of the results.

The authors point at an increase by 47% and 25% in Belgium and the Netherlands respectively, but these proportions concern different time periods. Over the comparable period of 2002 to 2008 the increase is about 23 to 24% in both countries. Schoevaerts et al. intended ‘to look into the pitfalls in analysing and comparing these data’, but overlooked this one. And more.

van der Post et al. (2013) didn’t get patients in perspective

Van der Post and colleagues report on the links between opinions about prior psychiatric treatment and risk of civil detentions in Amsterdam, the Netherlands. The authors conclude that a history of previous involuntary admission is associated with low treatment satisfaction and that more satisfaction seems to reduce the risk of civil detention. This is another way of saying that the three- to fourfold increase in the risk of repeated compulsory admission is mediated by patients’ perspectives. Unfortunately, these conclusions are not supported by the data from the Amsterdam Study of Acute Psychiatry.

Penterman et al. (2013) replicated a redundant model

In an earlier study Penterman et al. (2009) found that using the ‘Checklist Risk Emergency Service’ helped to predict aggressive behaviour of patients contacted by outpatient psychiatric emergency teams. The replication study (Penterman et al. 2013) also showed that a visual-analogue aggression scale (range 0 to 100) and one or more dangerous persons in the patient’s social environment (yes or no) are useful ‘predictors’ that arrive at 92% correct classifications (91% in the previous study).

The Journal is to be praised to give room for papers concerning the results of a replication study. However, in this case a prediction model was replicated that has no predictive value. For how good is 92% correct classifications?

Wilhelm et al. (2013) found no effect of an energy drink

Wilhelm, a psychologist affiliated with the department of Instruction technology at the University of Twente, together with three pupils of the Bonhoeffer College in Enschede, studied the effect of one can of energy drink on the outcomes of six cognitive tests. The study had a control group drinking water (n = 34), a placebo group that got sugar-free lemonade (n = 35) and the experimental group that received a caffeine drink (n = 34).

The longest cognitive test showed a statistically significant effect. This significant outcome was in the predicted direction, although the placebo group and experimental group ended up close. We are only informed that all other tests showed no differences between the three conditions. Differences in proportions and numbers of correct answers were tested using ANOVA. This statistical method, however, assumes that the dependent variable is continuously and normally-distributed with a constant variance. Proportions and numbers "by definition" do not follow a normal distribution. Possibly differences would have been found using more appropriate analyses (logistic- and poisson regression analyses). Moreover ...